These computers used to be manufactured by Acorn, but on 'Black Thursday' on 14 September, 1998, Acorn folded and has since been split up and sold off. The original machines are still manufactured and sold by Castle Technology, so the market is far from dead, despite the demise of the 'mother company'.

In the 1980s Acorn was the company that produced the BBC Micro. Since then they continued to develop their own proprietary desktop computer systems, based around the ARM chip, originally designed by them and now developed by ARM Ltd, a former subsidiary of Acorn. ARM stands for Advanced RISC Machine¹, and it is the RISC (Reduced Instruction Set Computer) architecture of the chip that allows its reduced power consumption and cheap fabrication. These properties make it ideal for portable computing, and most handheld devices and palmtop PCs use ARM chips. The speed of the chip make it ideal for graphics, and the N64 games console also uses them.

Despite this, however, Acorn systems never achieved great popularity outside the education market. The market is tiny compared with PCs - there are fewer than 100,000 users worldwide.

Why RISC is Best

RISC OS powered computers are superior to PCs in many ways:

• The operating system is not stored on the hard disc like Windows, but is held in ROM chips inside the computer. This means it cannot be corrupted by viruses, and that the computer is far faster to start up - typically taking under 15 seconds. Another effect of the OS being stored in chips is that even if the hard disc has been smashed apart with a sledgehammer, the computer will still boot, and you can use most of your software from floppy disc.

• There are very few viruses, and of these only one can cause serious damage. RISC OS is, of course, immune to all PC viruses.

• The whole system was designed in a far more modular manner that other operating systems, meaning that any programmer can easily trap events and calls to routines, and filter or replace them. The user interface is generally agreed to be easier to use and more consistent than the norm. For example, all fonts are anti-aliased, significantly improving display quality. (Anti-aliasing means that fonts are blended in with the background colour to remove jagged edges. PCs have only recently begun to do this, where as Acorn have been doing it since 1989. PC font blending is better described as 'smudging', and in many cases makes small fonts harder to read.)

• The software is all far more compact than on other platforms - typically 12 times smaller. It is also more consistent, and user friendly, with seamless integration between applications, allowing for much greater productivity. Data can be easily transferred between applications.

• Programmer support is far better on the RISC OS platform - typically within a few hours of e-mailing a bug report to a developer a new version of the software will be released. Compare this with Microsoft, where development can take weeks or months.

• Any Acorn machine can read discs formatted on both PCs and Macs, and can format and verify them quickly, too. Defragmenting hard discs is unnecessary on an Acorn - having the operating system in ROM and boasting memory efficient applications, there is less hard disk access and consequently far less fragmentation.

• Although RISC OS machines are sometimes more expensive than PCs they have an amazingly long shelf life, and this, combined with the bug-free OS and the durability of design, means that they are far more productive, especially for novices. Most users have never had to take a machine to be serviced. They also remain useful for far longer than PCs, typically more than a decade, and are more resistant to power surges et al.

• Programming genuinely is easy and simple on RISC OS. BASIC (a programming language) is included for free, and all the operating system calls are well documented in the public domain. The machine code assembly language (should you wish to use it) is unbelievably fast and simple, due to the RISC design of the CPU (only 20 instructions, and 16 registers).

A Quick Guide to RISC OS

Given how generally wonderful RISC OS is, here is a brief guide as to how to use it.

The Mouse

The first thing is that the mouse has three buttons². They are called, from left to right, 'Select', 'Menu' and 'Adjust'.

• Select is used for dragging, clicking, poking about with things, and is generally the main button. It is used to make an initial selection.

• Adjust is used as a subsidiary of select. For example, where in Windows you might hold down shift or control while clicking, in RISC OS you would use adjust. It is used to toggle elements in and out of selections, and to add extra selections without cancelling the current ones. Also, if you use adjust to click on a menu entry, or to 'OK' a dialogue box, the menu (or dialogue) will be kept open.

• The Menu button opens a pop-up menu. RISC OS doesn't use permanent menus, like Windows, as it was felt that these aren't dynamic enough, and a waste of screen real estate.

The Keyboard

Keyboards are usually the same, except that for historical reasons the 'End' key (next to 'Delete') is sometimes used as a 'Delete Right' key. Also, if you get one of the posh keyboards from Cerilica you get a little turn dial on the keyboard that can be used to change the volume on music players, re-scale and rotate graphics objects, or scroll around windows.

Finally with the keyboards, the function keys are used for common operations, instead of strokes like Ctrl-S, as are used in Windows. The ones you should be aware of are:

• F1 - help
• F2 - list of found
• F3 - save
• F4 - find
• F5 - goto
• F8 - undo
• F12 - enter command line (and other system functions, such as Shift-F12 - bring icon bar to front)

This means that these functions are quicker to use (once learned), and more consistent between applications.

The Desktop

In RISC OS the desktop is also referred to as the WIMP, or Windows Interface Management Program. It is one of the strongest features of RISC OS, and is fundamentally different to Windows because it isn't pre-emptive. That is, it waits for the user to lead it, and the user can perform many tasks at once. One of the most elegant features of the desktop is that you can easily move files and data between compatible applications (and most of them are compatible) by drag and drop.

The Icon Bar

The bar at the bottom of the screen is called the Icon Bar, and is a bit like the Taskbar in Windows, except that one icon is given to each application, and an application can have any number of documents (as opposed to Windows, where each window gets an icon). If the icon bar gets too full, it scrolls when you point at the ends.

On the left of the icon bar are the filing systems, such as the hard disc, floppy disc, commonly used applications, recycle bin (which may be hidden), RAM disc, and any compression filing systems that may be loaded.

On the right is the configuration icon, and on the far right, the task manager. From the latter you may change the allocation of system resources, such as how much memory each application gets.

The main method of controlling applications is to click Menu over their icon bar icon, and from the menu that appears you may get help, find out about the application (version number, status, author, for example), quit the application, and perform any number of application specific tasks. Clicking Select on an application icon typically opens a new document, or gives it control of the whole screen (for a game). Pressing F12 will return you to the desktop.

PC Emulator Cards

As well as offering file format compatibility with the Mac and the PC, and being able to read their discs, it is actually possible to plug a second processor into a RiscPC, providing native emulation for PC software, and letting you share resources. It is perfectly feasible to have both desktops running simultaneously, and many people prefer this since they can use both the industry standard (Windows), and the best (RISC) operating system.

'Killer Applications'...

One of the defence mechanisms evolved by users of RISC OS to cope with the dominance of PCs is the concept known as the 'Killer app'. These are products that are supposedly so brilliantly wonderful that thousands of users will defect from other platforms just to use them.

In the past, killer apps have included Sibelius (music notation software), ArtWorks (vector graphics) and Ovation (DTP). Sibelius has indeed been very successful, but ironically it is no longer available for RISC OS. This may change with the future release of a modern C++ compiler for RISC OS.

Currently-expected killer apps include Iron Dignity, a game that has been in development for the past four years, and Vantage, a revolutionary vector art package from Cerilica. It should, perhaps, be noted that many people have pointed out the similarities between 'killer apps' and cargo cultism...

Although not really a killer application, mention must now be made of the sad story of Pheobe. This was the final machine that Acorn designed before they collapsed, and many people expected it to do for Acorn what the iMac did for Apple. However, it never saw the light of day, and in many ways it was the ultimate white elephant.

New Machines

Acorn were sufferers from chronic, indeed terminal, 'Not Invented Here' syndrome. NIH stifled development of hardware, although fortunately Acorn did invent many wonderful things. A good example was expansion cards. The expandable cases were technically innovative and wonderful, but as to things to put in them, they didn't support either of the industry standards (ISA or PCI), which would have meant cheap and numerous quality hardware devices. This has all changed now, thankfully, but only because the market has been opened up for other developers.

In the dark days (pre-1998), Acorn was the only manufacturer of RISC OS machines. The development cycle went something like this: Acorn would go quiet for a bit, then they would announce one or more new designs, which would of course all be world beating³. Everyone would then be terribly optimistic for a few months, and claim that the end of the tunnel was in sight. Then there would follow a pause of about three years, in which time the rest of the computing industry would move on, and the machines would begin to look very out of date. And then the cycle would start again.

It is impossible to predict how things will go in the future, but there are currently three new machines under development:

• The Imago motherboard, designed by Millipede graphics.
• The various RiscStation machines, from RiscStation Ltd.
• And the Mico desktop machine, produced by Microdigital.

Finding Out More

The best way to find out about RISC OS is to march into any bookshop and look for Acorn User, in the computer section of the magazine racks, usually quite low down, buried beneath mounds of Apple-related publications.

The centre of the universe, as far as the RISC OS community is concerned, is RISC OS Ltd, the company set up after the collapse of Acorn to develop the operating system, which is now at version four.